1. Field of the Invention
The present invention is a method for treating human blood plasma prior to administering to a patient and, more particularly, is a method for removing blood group antibodies from the plasma to avoid incompatibility between donors and recipients of different blood groups.
Blood is a heterogeneous system in which a variety of cells are suspended in an aqueous solution (plasma) composed of proteins, lipoproteins and lipids in colloidal suspension and organic metabolites in solution. The cells include red cells (erythrocytes), white cells (leukocytes) and platelets (thrombocytes). Plasma is the solution which remains after the cells have been removed from the blood. Present in the plasma are various proteins, including antibodies secreted by the white cells as an immunological response to the presence of antigens in the blood, as well as proteins responsible for other essential physiological processes, such as the clotting factors required for hemostasis.
The major human blood group or type is determined by the presence of ABH antigens on the cell surface of the red blood cells. The antigens are oligosaccharides attached to glycolipids or glycoproteins in the plasma membranes of the red blood cells. The antigenic structure is of three types, referred to as "A", "B" and neither "A" nor "B" (that is "H" or formerly "O"). Either the A antigen, the B antigen, or both the A and B antigen may be present on the surface of an individual's red blood cells. Every individual's blood will contain naturally occurring antibody (primarily IgM) against the ABH antigens which are not present on his red blood cells. The situation is summarized in Table 1, which follows.
TABLE 1 ______________________________________ Blood Antigen On Antibodies Group Red Cell In Blood ______________________________________ A A substance anti-B B B substance anti-A AB Both A and Neither anti-A B substance nor anti-B H or O Neither A nor B Both anti-A substance and anti-B (H substance) ______________________________________
Individuals suffering from trauma which results in the loss of blood often require the transfusion of blood or blood plasma to compensate for the blood loss. Blood plasma is often used in place of whole blood because it is easier to store.
When transfusing plasma, incompatibility between the donor and the recipient arises whenever the donor's blood (and therefore plasma) includes antibodies to the ABH antigens, if any, present on the recipient's red blood cells. For example, plasma from a donor having group A blood cannot be transfused into a recipient having group B blood since the donor's plasma includes anti-B antibodies which would react with the recipient's blood. Thus, plasma from a donor having group H blood, which includes both anti-A and anti-B antibodies is incompatible with a recipient having any blood type other than H. Conversely, plasma from a donor having AB blood, which includes neither anti-A nor anti-B antibodies, is compatible with any recipient, regardless of blood group. Because of the potential for incompatibility, it has heretofore been necessary to carefully segregate the various types of plasma and maintain them separately so that plasma is not transfused into an incompatible recipient.
For the above reasons, it would be desirable to provide a treatment for removing the antibodies to the incompatibility antigens from plasma to provide a "universal" plasma which could be administered to any recipient regardless of blood type. Such treatment, however, must be highly specific to ensure that essential blood proteins, particularly the clotting factors, are not removed or inactivated. At present, there are at least 13 known clotting factors. Interference with the activity of any one of these factors in the transfused plasma could reduce the ability of the recipient's blood to clot. This is a serious problem since most plasma recipients are suffering from trauma which requires that their clotting function be unimpaired.
2. Description of the Prior Art
The use of immunoadsorption for the specific removal of anti-A or anti-B antibodies from the blood of patients about to undergo bone marrow transplants is known. See, Bensinger, et al., (1981) "Immunoadsorption for Removal of A and B Blood-Group Antibodies," N. Engl. J. Med., 304: 160-162; Bensinger (1981) Artificial Organs 5: 254-258; Bensinger et al. (1981) Transfusion 21: 355-342; and, Bensinger et al. (1982) Progress in Clinical and Biological Research 88: 295-300.